Not made on a Glowforge

Over in the Harlequin Pen thread the idea was tossed around to offset the layers in the laminated pen blank in order to provide better glue adhesion. The original pen had all the layers stacked with the seams in register so the segments in each layer had but joints along the kerf. Sideways it would be very stable but weak in the vertical axis.

I wanted to see what the same basic design would produce if the layers were offset so I whipped up a model in Tinkercad.

First I drew up three layers based on the original model but with the Y section offset. After importing to Tinkercad, I extruded the flat outline to 3mm layers - about 1/8 which is the nominal thickness of my wood stock. The layers started out like this:

Then they need to be stacked and centered on each other.

Once they are in register the two materials need to be split because the extrusion uses “Combine” and if the materials got combined they would have the same color. What is needed is to extrude the “walnut” and “maple” as separate pieces as shown here.

Putting the two extrusions back together shows us what the blank looks like after turning down to 14mm, the same thickness as the original.

If you want a better description of the modeling process I made a Pen Mold Visualizer Instructable with pix and video.

That tutorial is aimed at the intersection of 3D printing and woodturning but the process is the same for laser, once the blank is modeled. To make the 3D model for the pen mold I started with a flat SVG and extruded it in Tinkercad to full height.

To make the laser printed pen blank I also started with flat SVG, except I had 3 files which were each extruded to 3mm, repeated in contrasting material, then stacked.

Both processes end up with a (approx) 1"x1"x5" pen blank. Then an “extruder die” is made by putting a hole in the middle of a slightly oversize box, then inverting the resulting shape into a hole and combining it with the model.

Voila! The result is a visualization of what a pen would look like turned from the base model. In this case it saved me cutting the stock, assembling the blank and turning the pen tube since in the end I didn’t like the result. I did try it with several diameter extrusions but nothing looked as aesthetically pleasing as when the cut lines between light and dark intersect. (To me, anyway. Your mileage may vary.)

So, yeah, NOT made on a :glowforge: but I figured it is on-topic since the modeling technique might help others. Even if the project isn’t to be turned on a lathe. It might sound daunting to model up, say, 50 layers in 3D but it boils down to applying an extrusion to the cut files modeled for the laser. Want to make a laminated box? This is a way to do “what-if” to visualize the laminations with different stock thicknesses.

Hopefully someone will find it useful or it’ll spark an idea for something else.


This is great stuff.


This is really terrific. Thanks for the inspiration.


I’m a big fan of modeling to avoid wasting material, so I really like this approach. Thanks for the detailed explanation.


Sorry for posting that in the wrong topic!

This is helpful. I’m awful at visualizing this sort of thing and it never would have crossed my mind to model the design first. My creativity clearly lies in other areas. :slight_smile:


Since there are infinite number of ways to solve a problem in CAD, in a more feature rich cad than Tinkercad you could make the solid block and then “split” the model using planes in a vertical pattern (essentially what your 3D printing slicer software does with a solid model). Fusion has this as a standard feature (the slicer app of old is rolled inside fusion now) so you can take any solid geometry and produce a slew of sliced objects at some regular slicing interval (which for the laser you can export the face as a DXF or SVG). It is very confusing since the term “slicer” refers to both the CAM for 3D printing and this model splitting plugin inside Fusion.

since fusion deprecated the slicer app, the modern way of doing it is to make a vertical (or any other axis) of parallel lines. Then in the Manufacturing mode you can use Arrange to cause it to create slices of your model for sending to your CAM system (in our case the GF)


Nor would I, if I had not come up with the process to help me with 3D printing pen blank molds. It’s one thing when a cut file takes 90 seconds to print, another thing entirely when even a small 3D print takes hours.

I can try a dozen different cutfiles in the time it takes to 3D print one model so I generally burn through draftboard during the prototyping. If I had access to draftboard with different colors I bet it would never have occurred to me to model this in Tinkercad.

I think you mean “In a parallel universe where the CAD learning curve does not loom overhead like an impassible cliff wall…” :slight_smile:

I welcome the feedback on behalf of all the folks who read that and go “yup, makes sense.” I’m not in that cohort, but thanks!


That was my point actually. While I often use the laser to check a profile before a 3D print when it has to fit against something, even the fastest laser can’t beat how fast CAD can digitally slice a model and render it. I agree that most parametric CAD programs have a very steep learning curve (I teach a course in cad) but once you get over the hump it becomes second nature. Each cad program has it’s own automation quirks which once you learn greatly accelerate your actions. A cad teacher once told me the key to mastering cad, which is there is no “wrong” way as long as you end up with the right model; there are more efficient ways possibly, but no wrong.


For example:


Im new to wood turning, but this is an amazing way to get an idea of a final look. Very awesome, thanks for sharing!

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@tdotrob @henryhbk
I love what you guys do with CAD, 3D printers and modeling and this looks so interesting… I just wish I understood just what the heck you two were saying. I have wanted to “3D” for years. I can visualize what I want or need, but I have never been able to get over that proverbial “HUMP” to be able to grasp the software side. I have considered enrolling in one of the area tech schools, but currently none are offering anything is this subject.


I have a friend who has been teaching this stuff forever, but I have NO CLUE and have never used it. It feels intimidating to me. lol But it’s so interesting… (I should have asked her to teach me LOL)

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This resonates with me!